1. Field of the Invention
This invention relates to an apparatus for measuring the mass of particulates, which is used for the measurement or control of the concentration of particulates contained or dispersed in smoke exhausted from diesel engines, gas turbines, etc.
2. Prior Art Statement
In recent years, environmental pollution has become a serious social problem, and it is necessary to control the concentration of particulates in smoke exhausted from diesel engines, gas turbines, stirling engines, etc. through control of exhaust conditions.
Particulates in exhaust smoke mainly consist of dry soot in solid phase and sof in liquid phase. The solid component mainly consists of carbon black, while the liquid component consists of uncombusted fuel and lubricant and is whitish in color and not noticeable. Therefore, when exhaust conditions are controlled with the amount of dry soot as a criterion of the particulate concentration of the exhaust, there are cases in which an exhaust gas having light color and low dry soot concentration indicates an increased liquid component resulting from reduction of the solid component. In this case, it is necessary to measure the mass of the solid component and that of the liquid component separately for obtaining accurate control. Besides the case of exhaust smoke control, there are also other cases in measurement, regulation, research, etc. where it is necessary to measure separately the masses of the solid and liquid components of particulates dispersed in gas.
One technique for measurement of the mass of particulates is the oscillating microbalance method (U.S. Pat. No. 4,391,338). In this method, the total mass of particulates is obtained by capturing the particulates on a filter at a room temperature (i.e., 50.degree. C.) close to normal temperature, oscillating the filter with the particulates deposited thereon using an oscillator and measuring an inherent frequency change corresponding to the deposited amount of particulates.
While in this prior art technique the total mass of the particulates is obtained, the masses of solid and liquid components cannot be measured separately.